Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
In wind turbines that utilized gearboxes, the performance of the gearbox is critical to the successful operation of the wind turbine. As such, maintenance of the gearbox is critical. However, due to the size and location of the gearbox in the wind turbine, accessing the gearbox and various components thereof for maintenance purposes is difficult, time-consuming, and dangerous. For example, to maintain the gearbox, the gears and other components of the gearbox must typically be removed from the gearbox casing. These components can then be checked for damage, and can be repaired or replaced if necessary. The components must them be replaced in the gearbox casing.
Currently known methods and apparatus for performing such maintenance, and in particular for removing and/or replacing the components of the gearbox, are crude and in many cases can be dangerous both to the components and to the workers performing gearbox maintenance. For example, chains and lifting straps are typically tied to the gears of the gearbox, and the chains are then pulled to remove the gears. These removal methods, however, are unreliable and dangerous. In particular, current methods and apparatus have no way to take into account the angle at which the gearbox is disposed, which in some cases ranges from approximately 4 degrees to approximately 6 degrees. Rather, current removal methods, for example, remove the gears along a path that is not generally parallel to these angles, which can damage the gears being removed.
Accordingly, improved methods and apparatus for maintaining wind turbine gearboxes are desired. In particular, methods and apparatus for removing and replacing gears from the gearbox that are safe and efficient, and that account for the orientation of the gearboxes, would be advantageous.